Почему не работают методы map() и filter()?

import {Component, OnInit} from '@angular/core';
import {ActivatedRoute} from '@angular/router';
import {BlogService} from '../../../../services/blog-service/blog.service';
import { filter, map } from 'rxjs/operators';
@Component({
  selector: 'app-blog',
  templateUrl: './blog.component.html',
  styleUrls: ['./blog.component.css'],
  providers: [BlogService]
})
export class BlogComponent implements OnInit {
  public id: number;
  public blogs: any;
  constructor(private blog: BlogService, private activeLink: ActivatedRoute) {
    this.id = activeLink.snapshot.params['id'];
  }
  ngOnInit() {
    this.blog.getBlogs()
      .subscribe(data => this.blogs = data['blogs'])
      .map()
      .filter();
  }
}